1. Field of the Invention
The present invention relates to a playback device that performs at least playback from a recording medium such as an optical disc, and a management information acquiring method for acquiring the latest management information from the recording medium.
2. Description of the Related Art
Data recording/playback techniques exist which use optical discs (including magneto-optical discs) as recording media, such as a CD (Compact Disc), an MD (Mini-Disc), and a DVD (Digital Versatile Disc), for recording/playing back digital data. The term optical discs generically refers to recording media formed of a thin disc-like metal plate protected with plastic, onto which laser light is radiated and a signal is read by detecting variations in the reflected light.
Optical discs include, for example, read-only optical discs such as a CD, a CD-ROM, and a DVD-ROM, and recordable optical discs, such as an MD, a CD-R, a CD-RW, a DVD-R, a DVD-RW, a DVD+RW, and a DVD-RAM in which user data can be recorded. Data can be recorded on such recordable optical discs by employing recording techniques such as magneto-optical recording, phase-change recording, and dye-film change recording. Dye-film change recording is also called write-once recording and is suitable for data storage applications, since it permits recording of data only once and does not permit rewriting. On the other hand, magneto-optical recording and phase-change recording permit rewriting of data, and area thus used for various applications, including recording of various kinds of content data such as music, video, games, and application programs.
In recent years, a high-density optical disc called Blu-ray Disc (registered trademark) has been developed with a view to realizing a significant increase in capacity.
In such a high-density optical disc, for example, when data recording/playback is performed using a combination of a laser with a wavelength of 405 nm (i.e., so-called blue laser) and an objective lens with an NA of 0.85, approximately 23.3 GB (gigabytes) of data can be recorded on or played back from a disc having a diameter of 12 cm. In this example, this capacity is achieved when the disc has a track pitch of 0.32 μm, a linear density of 0.12 μm/bit, and a format efficiency of approximately 82% with a recording/playback unit of a 64 KB (kilobytes) data block.
Write-once types and rewritable types of such high-density optical discs have also been developed.
As a type of Blu-ray disc, for example, BD-R (Blu-ray Disc Recordable) which can be written to only once has a TDMS (Temporary Disc Management Structure) as management information for managing the data recording structure or disc defect information, and it is specified that the TDMS be additionally recorded to a TDMA (Temporary Disc Management Area) that is a management information recording area provided at a predetermined position on the disc. The last additionally recorded TDMS is the latest (that is, a valid) TDMS (see FIGS. 5A to 5D).
A plurality of TDMAs are provided in the lead-in area or data area at the inner radius of the disc, and a serial number such as TDMAn (n=0, 1, 2, and so on) is assigned to each individual TDMA. It is specified that the TDMAs be used in the order of their numbers, as in the order of TDMA0, TDMA1, TDMA2, and so on, and that the TDMSs be recorded to each TDMA successively in order from the beginning of the TDMA.
In this regard, each TDMS to be additionally recorded sequentially into the TDMA as mentioned above stores an SRRI (Sequential Recording Range Information: management information about the recording structure of data in the user data area) and, as required, a TDFL (Temporary Defect List: management information about defects on the disc) (for example, see FIG. 6C). Further, in this TDMS, a TDDS (Temporary Disc Definition Structure) as pointer information for indicating the recording position of the latest information (that is, the last recorded information) of the TDFL, SRRI is stored in its last sector.
Due to the above-mentioned structure of the TDMS, to acquire the latest management information (SRRI or TDFL) recorded on the disc on the drive device side, first, with respect to the latest TDMS recorded last in the TDMA, the above-mentioned TDDS in its last sector is read. Then, data is read from a position pointed to by the pointer information in the read TDDS, so the latest management information can be acquired.
The related art techniques are disclosed in Japanese Unexamined Patent Application Publication No. 2006-85859 and Japanese Unexamined Patent Application Publication No. 2006-114107.